Continental Focus, International Reach

Unique Seaflex Performs Feat Offshore Tunisia

Thursday, January 30, 2014

Tunisia saw a technological feat take place off its coast recently when Unique Seaflex, a Unique Maritime Group company, facilitated an underwater lift project. According to the company the project, carried out in 300 meters of water, was one of the most complex underwater lift projects completed.

The project, a decommissioning, was carried out on the Oudna field for Lundin Tunisia BV who holds a 40% stake and is operator of the field. At end of the field’s viable lifecycle, a problem arose of how best to decommission the FPSO – and in particular how to take care of the delicate operation of disconnecting several hundred tons’ worth of moorings without incident.

Technical discussions between Lundin and Unique Seaflex led to a plan of using a combination of 41 different-sized parachute-style Air Lift Bags (ALBs) of up to 50 tons in size to be installed on the moorings to reduce their tension to a manageable level. The deck-mounted linear winch was rated to 450 ton, but because the three mooring anchors were extremely well embedded in the sandy seabed, the effective tension on the chafe chain would have increased by an estimated 1.5 to two times the original 400 tons.

The use of Unique Seaflex ALBs allowed the deck-mounted linear winch to pull on the chafe chain so as to slacken the connection to the Ikdam deck hook. The connecting shaft was then pulled out from the wren hook and by doing so, freed the chafe chain thus allowing the mooring system to gently be lowered on a wire, thereby de-tensioning the system. Once released, the chafe chain was transferred to a nearby AHTV which held the de-tensioned mooring system whilst the Ikdam FPSO disconnected.

Along with the fleet of ALBs, Unique Seaflex also supplied all the heavy duty shackles and lifting slings as well as an air inflation/deflation system and a topside technician to oversee the operation and ensure the safest and most efficient use of the package of equipment.

Commenting on this occasion, Graham Brading, MD for Unique Seaflex said, “Whilst we do supply standard buoyancy products to solve standard buoyancy problems, Unique Seaflex is always dedicated to bring out world-class solutions when clients describe their operational challenges and ask us to work with them to develop methods which will deliver them the best possible technical, operational and commercial outcome.”


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